The present invention is a two-knuckle hinge for passing electrical current.
A number of applications exist where it is necessary to provide a source of electric current within a pivotable door or window, in which case it is necessary to pass an electrical wire or wires from the frame of the door or window to the door or window itself. Examples of such applications are electrically operated door latches, card activated entry systems, door locking mechanisms which automatically release the door in the event of a fire, and electrical systems to monitor and energize alarm systems. Typically, electricity is passed to the door through a wire disposed in one of the door hinges.
Several hinge constructions are known for passing an electrical wire to the door. In such known hinges, an electrical wire enters the rear face of one of the hinge leaves, and extends through conduits to the other hinge leaf, whereupon it exits again through the rear face of the other hinge leaf. Preferably, the electrical wires are concealed totally within the hinge so as to protect the wire from damage or tampering. Lawrence U.S. Pat. No. 4,116,514, the Crane et al. U.S. Pat. No. 3,857,625, and the Peterson U.S. Pat. No. 3,838,234 disclose examples of known arrangements. In each device a wire, extending through one hinge leaf, is directed to the other leaf through a longitudinal bore drilled or formed in the hinge pin extending between adjacent hinge knuckles. While such a configuration acts to conceal the wire in the hinge, the formation or drilling of a bore through a hinge pin is undesirable from the standpoint of cost, and tends to complicate the design in comparison to a corresponding non-electric hinge.
An alternate construction for passing a concealed electrical wire from one hinge leaf to the other is disclosed in U.S. Pat. No. 3,842,386 in the name of Charles R. Suska, the inventor herein. The facing bores of two adjacent hinge knuckles are enlarged in the vicinity of their abutting ends to provide an annular cavity, between the hinge pin and knuckles, common to the two knuckles. An electrical wire, introduced from one hinge leaf into the cavity of its corresponding hinge knuckle extends along the hinge pin into the cavity of the adjacent hinge knuckle and out through a conduit in the other hinge leaf. This avoids the necessity of having to drill a hole in the hinge pin.